In order to simplify and optimize the flight planning process for pilots a number of computerized flight planning services have been developed such as the Lockheed Corporation's Jet Plan service. By utilizing a terminal connected to a centralized database a pilot can generate a flight plan for a particular destination. The computer database will include routing information such that the optimum route between a destination and a departure airport can be automatically generated, weather information including terminal weather, winds aloft, area forecasts and SIGMETS as well as performance data for various types of aircraft such that the flight plan can be otpimized automatically to take into account the characteristics of the aircraft.
However, the existing computerized flight planning services have a number of limitations including the fact that it is necessary for the pilot, after the flight plan has been generated on his terminal, to take the printed copy of the flight plan and enter it manually into the aircraft navigation or flight management computer. This process in the past has been limited to route and waypoint entry only, not including leg-by-leg fuel, time and cruise mode parameters. Further, the manual process is tedious and can also result in erroneous inputs to the navigation system. The existing flight planning systems also suffer from the disadvantage that they are unable to provide for changes in flight plans once the aircraft is airborne. It is not uncommon for flight conditions such as weather to change or for the air traffic control situation to limit the availability of flight levels. Existing systems do not provide a convenient method for requesting and receiving an updated optimized flight plan from the aircraft in flight.
Another limitation of the currently available flight plan systems is that there is no convenient way to monitor the progress of the aircraft against the flight plan. For example, for any position between the specified waypoints on the flight plan, it is necessary for a pilot to either mentally interpolate flight plan data such as fuel usage or to use a pencil and paper or calculator to generate the data that he can compare to the aircraft's actual progress. Similarly there is no convenient way for the pilot utilizing existing systems to get appropriate weather updates that can be integrated into the flight plan while the aircraft is in flight.